The invention relates to a method and system for transporting a hydrocarbon fluid, such as crude oil and/or natural gas.
It is customary practice to install pipelines for transporting a hydrocarbon fluid in trenches that are subsequently filled with soil and/or rocks to bury and protect the pipeline against damage.
A problem with this known pipeline installation technique is that it is expensive to make deep trenches in the earth crust, so that the trenches are generally only a few meters deep, which may not be adequate to protect the pipeline against freezing and/or ice damage if it is laid in an underwater and/or cold environment, such as an arctic and/or permafrost region.
It is also known to install underground pipelines in U-shaped boreholes that are drilled using a so-called river-crossing drilling technique.
A problem with this known technique for installation of underground pipelines in U-shaped boreholes is that it is difficult to pull the pipeline into and through the U-shaped borehole that may at least partly collapse or otherwise get plugged before or while the pipeline is pulled into and through the U-shaped borehole. This known technique for installing underground pipelines in U-shaped boreholes is therefore only suitable for installing pipelines of a length that is limited to only a few hundred meters up to a few kilometers in favorable conditions, for example in a stable formation that does not collapse after drilling of the U-shaped borehole.
It is also known from International patent application WO 2012/095472 to line an oil or gas production well with a tubular that is circumferentially expanded after insertion into the borehole. In this known well lining technique the liner is inserted and expanded continuously while the borehole is being drilled, so that the expanded liner stabilizes a large fraction of the borehole during the drilling process. This known borehole drilling technique is suitable to drill boreholes with a length of several kilometers, which may in favorable conditions be up to about 25 kilometers.
If pipelines are laid to transport crude oil from a production site to a processing and/or distribution site in for example arctic, underwater or otherwise difficult accessible and/or environmentally sensitive regions then there is a need to install pipelines that may span a lateral distance of several hundred or even several thousand kilometers without generating significant environmental impact caused by digging deep trenches in the earth crust.
Therefore there is a need for an improved method and system for transporting hydrocarbon fluid over long distances, wherein the pipeline is adequately protected and a minimum of environmental impact is generated. Furthermore, there is a need for an improved method and system for transporting hydrocarbon fluid over long distances in arctic regions, such that at least a significant part of the pipeline system is adequately protected from frost, permafrost, moving ice and/or an instable overburden above a frozen underburden.